An exhaust system associated with an engine may include an emission reduction system for delivery of a reductant into an exhaust stream exiting the engine. The emission reduction system may include various components, such as a tank for storing the reductant, a pump, a reductant dispensing device, and reductant delivery conduits. The reductant delivery conduits may provide fluid communication between the components of the emission reduction system for passing the reductant therethrough. The reductant from the tank may be supplied to the reductant injector via the pump.
After engine shutdown, some quantity of the reductant may be retained within the components of the emission reduction system located downstream of the reductant tank with respect to a reductant flow direction. The reductant is susceptible to freezing in cold environments. For machines operating in relatively cold environments, the reductant retained within the components of the emission reduction system may freeze, which may in turn affect performance of the exhaust system. Therefore, exhaust systems may benefit from an ability to purge the components of the emission reduction system.
US Published Application Number 2015/0047321, hereinafter referred to as '321 reference, describes a system and method for delivering a vehicular fluid to a component of the vehicle. A reductant delivery system of a selective catalytic reduction system delivers the vehicular fluid to the component of the vehicle. The reductant delivery system includes a compressed air source, a tank in fluid communication with the compressed air source, a dosing module in fluid communication with the tank, and a control module electrically coupled to the compressed air source. The tank may contain a diesel exhaust fluid and the dosing module is in fluid communication with the component that receives the diesel exhaust fluid. The control module regulates an amount of air pressure in the tank to deliver the vehicular fluid to the dosing module. The system omits a vehicular fluid pump such that the compressed air from the compressed air source pressurizes the dosing module with the vehicular fluid.
The reductant delivery system described in the '321 reference relies on the compressed air source for supplying the compressed air to perform purging operations. Such usage of the compressed air for purging operations may deplete compressed air in the compressed air source. Thus, a high capacity compressed air source may have to be associated with the reductant delivery system, which in turn may increase overall cost associated with the reductant delivery system.